Universal electric motor



1936- (5. P. DAEGER 2,046,675

UNIVERSAL ELECTRI C MOTOR Filed Aug. 24, 1934 INVENTQR Gearye R Dazlqer ATTO R N EY W 'MM Patented daily 7, 1936 The present invention relates to suction cleaners in general and particularly to a new and novel electrical circuit for a universal type suction cleaner motor combined with a headlight. .More specifically the invention comprises auniversal electric motor for a suction cleaner or similar tool adapted for use over a range of Irequencies' and voltages, in combination with a substantially constant voltage electric light which is so connected to the motor circuit that variations in applied voltage and frequency to the motor produce minimum voltage variations across the lamp terminals.

It is an object of the present invention to provide a new and improved combination motor and electric light circuit for a suction cleaner, or similar machine. It is another object of the invention to disclose an improved electrical circuit for an electric motor combined with an electric light 0 circuit, the elements being so related that variations of voltage and frequency across the motor terminals produce minimum variations oi! voltage across the light. These and other more speciiic objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate. Referring now to the drawing in which preferred embodiments oi the present invention are disclosed:

Figure 1 is a showing of a modern suction cleanor including a motor and a headlight, illustrating cuit or the present invention is adapted to be embodied:

Figure 2 illustrates diagrammatically a pre- 7 ierred embodiment of the invention;

Figure 3 is a diagrammatic illustration of the electrical circuit or a second preierredembodiment.

Small floor tools, such as suction cleaners and floor polishers, are normally provided with a universal electrical motor adapted to run upon N direct current and upon alternating currents of various freuuencies and voltages. Commonly the motor of such tools is adapted to run upon direct current at a certain voltage and upon alternating currents up to 100 cycles at higher voltages. The 56 motor is designed to deliver equal power outputs throughout this range when the voltage is varied as the frequency varies. This universality oi. the motor makes possible the use of the machine under diflerent conditions and in diflerent localities. Y

UNlTED STATES,

UNIVERSAL ELECTRIG MOTOR Application August 24, 1934, Serial No. 741,198

I 5 Claims. (Cl- 172-276) the type of machine in which the electrical cirscrews PATENT OFFEQE The inclusion in the small tool of an electric headlight which is so positioned that light rays therefrom are directed forwardly of the machine so as to illuminate the surface being operated upon is an important innovation and one which considerably increases the efiectiveness of the machine through making possible a more inteliigent operation thereof. For this purpose an electric lamp is used which is connected to the circuit or. the motor. in view of the fact that the life of an electric light may be said to vary inversely as the 13th power of the voltage, it is entirely obvious that it is desirable to maintain the voltage on the lamp as nearly constant, and at the voltage for which'the lamp was designed, as is possible. In the electrical circuit designed in accordance with the present invention vari-' ations in the power supply, both in frequency and in voltage over the range for which the machine motor was designed, produce a minimum voltage variation across the lamp terminals.

Referring now to Figure 1 in particulars. modern suction cleaner is disclosed comprising a main body I, a dust bag 2 and a handle 5.3. Within the motor casing of body i is positioned an electric motor, indicated generally by the reference character d, which is supplied with electricity by incoming power leads of conductor ii. The leads enter the upper end of the handle near the manually operable electric switch 6 and pass downwardly therethrough to the handle bail l at which point they are passed through a separable plug 8 and directly into the motor casing. Within the motor casing, and immediately behind a forwardly facing opening therein, is positioned an electric light 9 which is connected to the motor circuit in a manner which will be hereinafter fully disclosed. The switch for the light circuit is indicated at Ill and is positioned at the rear of the motor casing so that the machine may be ,operated without the light, if desired.

Referring now to Figure 2 in particular a prefer-red embodiment of the electrical circuit for the motor and the iight' is disclosed. The motor is seen to comprise an armature 2E3 and a field winding or windings. On one side of the armature is connected a field winding it and upon the opposite side oi which are positioned field windings, or divisions of a field winding, 22 and 23. In low speed operation, both field coils 22 and 28 are in series with the armature and field coil 2 i. In high speed operation field coil 23 is omitted from the current path, and the field strength being reduced, the motor rotates at a higher [iii speed. To make this speed control possible a lead 25 is connected between field cells 22 and 23 and, together with conductors 24 and 26 which conmeet to the outside terminals of j coils 2i and '23, passes through the plug 8 and up to the handle switch 6. Switch 6 is of the three-position type and is adapted to place either lead it or lead 25 in series with the incoming power lead 21. Lead 26 does not pass through the switch.

According to this embodiment of the invention the circuit of lamp 9 and switch NJ is formed by a conductor 28 which connects to the incoming lead 2? on the line side of switch 6, passes through the four prong plug 8, connects lamp ii and switch it in series, and is tapped to a midpoint of field coil 2|. Being so connected current can pass through the lamp with the motor same portion, comprising both. resistance and reactance, being sufiieient in alternating current operation throughout the range of motor use, to produce suhstantially constant lamp voltage. The reactance varies with the frequency and as the impressed motor voltage is higher with higher frequencies the increase in ieactance tends to minimize the voltage change directly across the lamp. terminals.

Referring now to Figure 3 in particular a second preferred embodiment of the invention is disclosed. According to this embodiment the conductor t8 which connects the lamp 9 and its switch ill to the motor is connected from a point between field coil 2| and armature to the outside of the outer or low speed field coil 23. With the lamp so connected the-circuit has the advantage that the plug 8 at the junction of the handle and the handle bail need only beta. three prong plug whereas in the first embodiment four prongs were necessary. According to this embodiment the entire field coil 28 is in series with lamp circuit and no intermediate tap on that coil is required.

With the motor in high speed operation. in

which only held coils 2i and 22 would be connected in series witharmature '20, it is seen from the diagram that field coil 23 isin series with the lamp whereas in the low speed operation the lamp circuit is connected in parallel with field coil 23.

In high speed operation oi the machine the impedance oi the coil 23 acts to reduce the voltageaosaers age increasing with the frequency; and comprisfield windings being divided and there being source of power, and a light adapted for a lowerdirectly across the lamp terminal but the transiormer action of the same coiltends to increase the voltage thereacross. The result is a reduction in the variation in voltage across the lamp throughout the range of voltages ior which the motor is designed.

I claim:

1. In combination, a universal electric motor having an armature and a divided field winding. an electric switch to connect selectively all or part i of said winding in serieswith said armature for low or high speed operation, and an electric light connected in series with a part of the winding of said motor,

2. The structure recited by claim 1 inwhich 15 said light is connected to an incoming power source beyond said switch and is in parallel with said armature and all out a part ofv said field winding.

3. In combination with a universal motor in- 20 eluding, an armature and field windings connected thereto and in series therewith, one of said field windings being divided and there being switch means to connect selectively all or only part thereof to a source of power, and a light adapted for a lower-than-motor voltage tapped to a mid-point of a second field winding and connected to the power supply on its opposite side.

4. In combination with a universal motor adapted for use with electric power sources varying in frequency and applied voltage, the volting an armature and a field winding. an electric light connected in series with a portion oi said fieldwinding having resistance and reactance,

switch means selectively to connect said armsture and all or only part of said windings to a than-motor voltage connected across said arms-Z ture' and said divided winding, said light being connected inparallel with said armature and the entire divided winding when all 01' said wind-' ing is connected to a. source 01' power, and being connected in series with a part 01' said winding when only a part thereof is connected to a source ofpower, the part of said winding when in seties with said light being subjected to a transformer action tending to raise the lamp voltage. 3 GEORGE P. DAIGER. 

